It is not uncommon to employ resilient blocks of material, such as, plastic foam within innerspring mattresses as a part of the original assembly process. Typically, the resilient blocks traverse a limited portion of the mattress, such as, the intermediate portion and requires manual pulling of the foam or block between innersprings. Characteristically, such mattresses are advertised as being reinforced but in such cases typically the reinforcing blocks do not fully occupy the space between innersprings and, for example, do not traverse the entire length or breadth of the mattress. Furthermore, when used as a part of the original manufacture of the mattress, the principal support elements are the spring members.
In the stuffing or restoring of cushions, it has been proposed to use various types of insert tools but primarily have been concerned with the insertion of relatively loose fill or stuffing material. Representative patents illustrating various approaches that have been taken in the past are British Patent No. 352,386 to L. Iske and U.S. Pat. Nos. 1,334,745 to E. C. Farr; 1,722,734 to T. Coghlan et al and 3,310,613 to H. J. Lundberg. In the latter, a foaming composition is inserted into a fabric envelope which is inserted into position and then allowed to "foam in place".
Other patents of interest in this field are U.S. Pat. Nos. 1,484,869 to H. G. Brandwein; 1,592,308 to G. C. McCullough; 1,672,305 to C. F. Coda; 1,669,721 to G. C. McCullough; 4,517,723 to R. Tschan; 4,570,323 to B. E. Legerius et al; and 4,761,872 to C. J. Buettner et al.
This invention is concerned with large innerspring mattresses of the type in which the innerspring coils are not encased in any fabric and are constructed so that the individual coils are aligned so as to leave a substantially uniform space between adjacent rows of coils. In the past, even though the outer cover of a used mattress exhibits little or no wear, the mattress must be discarded because of damage to individual coils or loss of desired firmness in particular sections of the mattress. Innerspring mattress constructions of this type presents different problems than those confronting one concerned with restoring furniture or smaller cushions. Thus, in order to restore a used mattress to its original condition, the desired degree of firmness must be reestablished in a vertical direction, it should provide a level sleeping surface with no hard or soft spots and should be returned to its original shape or designed firmness and be maintenance free. Another consideration is that typically the less expensive mattresses have a smaller number of coils per unit area and therefore a larger space between rows of coils which must be filled to support the coils for the desired resiliency as well as forcing the coils back to their original position so that the coils work properly in a vertical or up-and-down direction as opposed to falling sideways as the coils have a tendency to do when they become old and lose their elasticity, or the connecting wires become severed.
As demonstrated by the patents previously referred to, it has been proposed to provide different filling materials for cushions. Typically, the filling has little or no elasticity and does not provide a level sleeping surface. If the materials used to fill the voids between the coils are too soft, they fail to offer the support necessary for the coils to return the mattress to a firm and level sleeping surface. Moreover, for larger mattress areas to be restored, loose fill or foam-in-place materials are difficult to insert and to uniformly fill a space or void. On the other hand, use of self-contained materials have, as earlier noted, been used in the construction of the mattress as a piece of original equipment where the materials are manually inserted into limited sections of the mattress; to the best of our knowledge, however, no one has satisfactorily devised a method or tool by which resilient blocks of material can be inserted between rows of innersprings in a used mattress throughout the entire length or breadth of the mattress and in such a way as to restore the desired firmness or resiliency to the mattress in a relatively simple and low-cost, highly efficient manner.